[llvm] [TableGen] Support automatic type deduction (PR #109434)

[Rahul Joshi via llvm-commits]

jurahul wrote:

Especially for code like:

```
class Intrinsic<list<LLVMType> ret_types,
                list<LLVMType> param_types = [],
                list<IntrinsicProperty> intr_properties = [],
                string name = "",
                list<SDNodeProperty> sd_properties = [],
                bit disable_default_attributes = true> : SDPatternOperator {
  string LLVMName = name;
  string TargetPrefix = "";   // Set to a prefix for target-specific intrinsics.
  list<LLVMType> RetTypes = ret_types;
  list<LLVMType> ParamTypes = param_types;
```

where param_type and ret_types have their type declared, so we can avoid repeating it again in `RetTypes` and `ParamTypes`.

https://github.com/llvm/llvm-project/pull/109434